*{
    margin:0;
    padding:0
}
.menu{
    width: 100%;
    height: 50px;
    background-color: black;
    display: flex;
    flex-wrap: nowrap;
}
.item{
    flex: 1;
    color: aqua;
    text-align: center;
    line-height: 50px;
}
.active{
    background-color: red;
}